sio1007: Properly build '.c' files

Properly build the super i/o .c files.  This prevents including
the .c file directly in romstage, which is generally bad practice.
Adding a Makefile and a .h file to include.

Change-Id: I0be66e94d3062a2c4a445cee2f12ec249598dc8b
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/4014
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
4 files changed